This is a note to let you know that I've just added the patch titled tcp: do not set rtt_min to 1 to the 4.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: tcp-do-not-set-rtt_min-to-1.patch and it can be found in the queue-4.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 372022830b06d9980c7e8b41fa0a4081cff883b0 Mon Sep 17 00:00:00 2001 From: Eric Dumazet <edumazet@xxxxxxxxxx> Date: Thu, 11 Feb 2016 08:58:18 -0800 Subject: tcp: do not set rtt_min to 1 From: Eric Dumazet <edumazet@xxxxxxxxxx> commit 372022830b06d9980c7e8b41fa0a4081cff883b0 upstream. There are some cases where rtt_us derives from deltas of jiffies, instead of using usec timestamps. Since we want to track minimal rtt, better to assume a delta of 0 jiffie might be in fact be very close to 1 jiffie. It is kind of sad jiffies_to_usecs(1) calls a function instead of simply using a constant. Fixes: f672258391b42 ("tcp: track min RTT using windowed min-filter") Signed-off-by: Eric Dumazet <edumazet@xxxxxxxxxx> Signed-off-by: Neal Cardwell <ncardwell@xxxxxxxxxx> Cc: Yuchung Cheng <ycheng@xxxxxxxxxx> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- net/ipv4/tcp_input.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -2926,7 +2926,10 @@ static void tcp_update_rtt_min(struct so { const u32 now = tcp_time_stamp, wlen = sysctl_tcp_min_rtt_wlen * HZ; struct rtt_meas *m = tcp_sk(sk)->rtt_min; - struct rtt_meas rttm = { .rtt = (rtt_us ? : 1), .ts = now }; + struct rtt_meas rttm = { + .rtt = likely(rtt_us) ? rtt_us : jiffies_to_usecs(1), + .ts = now, + }; u32 elapsed; /* Check if the new measurement updates the 1st, 2nd, or 3rd choices */ Patches currently in stable-queue which might be from edumazet@xxxxxxxxxx are queue-4.4/bonding-prevent-out-of-bound-accesses.patch queue-4.4/tcp-do-not-set-rtt_min-to-1.patch